Crawl Space Humidity: What You Need To Know

Introduction

Is crawl space humidity a problem for you? If so, it’s crucial to understand the importance of maintaining proper humidity levels in the crawl spaces of your home. Crawl spaces, typically found in homes with basements or slab foundations, often go unnoticed when it comes to home maintenance. However, neglecting crawl space humidity can lead to various issues such as mold growth, wood rot, structural damage, and even pest infestations. In this comprehensive guide, we will explore the significance of these moisture levels, provide tips on measuring and controlling it, and discuss ideal crawlway humidity levels. So let’s dive in….

Understanding Crawl Space Humidity

1.1 What is Crawl Space Humidity

Crawl space humidity refers to the amount of moisture present in the air within the space below your home. This space is also commonly referred to as a crawlway, a basement passage or a basement channel. It is essential to maintain the ideal crawl space humidity level, which ranges between 30% and 50%. However, many homes have crawl spaces with relative humidity levels above 60%, which can lead to various problems. Excessive humidity on the other hand can lead to structural damage not to mention energy loss and impact the overall comfort and integrity of your home.

1.2 What Causes Crawl Space Humidity

Crawl space humidity is created by various factors that contribute to the presence of moisture in the air within the basement channel. Here are the causes that can lead to this humidity:

1.2.1 Moisture from the Ground

Crawl spaces typically have dirt floors, and the dirt releases moisture that combines with outside humidity, creating favorable conditions for fungal growth, damp wood structures, and pests.

1.2.2 High Humidity Levels

High moisture levels in the surrounding environment can contribute to crawlway humidity. When the air outside is humid, the moisture can penetrate the crawlway space and increase its humidity.

1.2.3 Water Intrusion

Water intrusion from sources such as flooding, broken or leaking pipes, sewer backups, or groundwater can introduce excessive moisture into the crawl space. This water can contribute to high humidity levels if not properly addressed.

1.2.4 Inadequate Ventilation

Poor ventilation in the crawl space restricts air circulation, trapping moisture inside and leading to increased dampness levels. Insufficient airflow hinders the natural drying process, allowing humidity to accumulate.

1.2.5 Condensation

Condensation occurs when warm, humid air comes into contact with cool surfaces, causing moisture to form. If there are cold surfaces or inadequate insulation in the basement channel, condensation can occur and contribute to the increase of humidity in the space below your home.

1.2.6 Lack of Moisture Control Measures

The absence of moisture control measures, such as vapor barriers, moisture barriers, and proper drainage systems, can allow moisture to enter your home’s crawlway space and increase dampness levels.

1.3 The Consequences of a High Crawl Space Humidity Level

As stated above, crawl spaces, commonly found in homes with basements or slab foundations, can be prone to high humidity levels if not properly ventilated and maintained. The consequences of a high crawl space humidity level can be significant and result in various problems. Let’s examine the most common and serious in detail.

1.3.1 Wood Rot

High levels of moisture in your basement passage can lead to wood rot, a condition caused by fungal growth that deteriorates the structural integrity of wood materials. When moisture and oxygen are present, certain types of molds and fungi can thrive and feed on organic materials like wood. Wood rot can gradually destroy wooden structures, such as floor joists, girders, and sill plates, leading to sagging floors, cracks in walls, and other structural issues.

1.3.2 Structural Damage

Alongside wood rot, high crawl space humidity levels can cause structural damage to the entire building. Excessive moisture can weaken the structural components, compromising their strength and stability. The damp conditions can affect not only wooden materials but also other building elements, such as concrete foundations and metal supports. Over time, this can in fact lead to significant structural issues that require costly repairs and jeopardize the safety of the building.

1.3.3 Mold Growth

Mold is another consequence of high crawlway humidity levels. Mold spores are present in the air and can settle and grow on various surfaces when moisture is available. Crawl spaces with elevated humidity provide an ideal environment for mold growth. Mold can affect different organic materials, including wood, paper, carpet, and insulation. It can cause discoloration, produce unpleasant odors, and contribute to poor indoor air quality. As a result, prolonged exposure to mold can lead to health issues, including allergies, respiratory problems, and potential mycotoxin exposure.

1.3.4 Insect Infestation

Insects are attracted to high moisture environments, and a humid crawl space can become a breeding ground for various pests. Termites, wood-boring beetles, and other insects are particularly drawn to moist wood. They can infest and damage the structural components of the building, exacerbating the effects of wood rot and compromising its stability. In addition to insects, other critters like mice, rats, and snakes may be attracted to a damp crawl space, seeking shelter and a water source.

1.4 Measuring Crawl Space Moisture Levels

Before you can maintain or regulate your crawl space moisture level, you need to know what it is. You can use various methods and tools to get an accurate reading. Here are some commonly recommended approaches:

1.4.1 Hygrometer

You can accurately measure your crawl space moisture level by using a digital hygrometer. A digital hygrometer is a device specifically designed to measure humidity levels. Place the hygrometer in the center of the space to obtain accurate readings of the relative humidity.

Hygrometers are available in both analog or digital formats. Some models even offer wireless connectivity for remote monitoring. The digital units are extremely accurate.

1.4.2 Data loggers

Data loggers are electronic devices that record and store humidity data over a specific period. These devices can be placed in space below your home to continuously monitor and log humidity levels.

You can then retrieve the recorded data and analyze it. It will help you gain insights into the existing humidity patterns.

1.4.3 Smart Home Devices

Smart home devices equipped with environmental sensors, such as smart thermostats or home security systems, often include humidity sensors.

These devices can provide dampness readings and allow you to monitor and control the crawl space humidity level through a connected app or voice command.

Maintaining Ideal Crawl Space Humidity

2.1 The Ideal Crawl Space Humidity Level

So, what should crawl space humidity be….
To ensure a healthy crawl space, it is important to maintain the ideal humidity level between 30% and 50%. This range inhibits mold growth, prevents wood damage, and discourages pests from thriving in the crawl space . This is well described in the crawl space humidity chart below:

Monitoring and controlling humidity levels are essential to achieve these optimal conditions. To achieve and maintain the ideal crawl space humidity levels, several measures can be taken:

2.2 Methods to Lower Basement Channel Humidity

2.2.1 Crawl Space Ventilation

Proper ventilation is crucial for controlling the humidity levels in the space below your home. For this reason, you can install a vent or a crawl space ventilation fan.

This will allow air circulation, which helps reduce moisture buildup. However, it’s important to note that in humid climates or during certain seasons, ventilating the crawl space may introduce more moisture and be counterproductive. Therefore, you should use ventilation judiciously and adjust it based on the climate and specific conditions of your home.

2.2.2 Vapor Barriers and Moisture Barriers

Installing vapor barriers or moisture barriers can significantly reduce moisture and help you acheive your ideal crawl space humidity level. People typically make these barriers out of plastic sheeting, and they place them on the crawl space floor and walls. They prevent moisture from the ground and surrounding environment from entering the space, thus maintaining lower levels of humidity. This is also known as encapsulating the crawl space.

2.2.3 Crawl Space Dehumidifiers

Using a crawlspace dehumidifier is an effective way to control crawl space humidity. Dehumidifiers extract excess moisture from the air, maintaining optimal humidity levels. When choosing such a unit, consider its capacity, energy efficiency, and noise level. Place it in a central location within the crawl space to ensure proper air circulation and maximum effectiveness.

Click on the following link to access our blog post titled “Crawl Space Dehumidifier: What You Need to Know“. There you will find out how you can determine the size of the unit that you need, the steps you need to take for its preparation and installation and how to maintain the unit for optimal moisture control.

2.2.4 Proper Drainage

Ensuring adequate drainage around the foundation of your home can prevent water seepage into the crawl space. In fact, well-functioning gutters, downspouts, and proper grading can redirect water away from the foundation, minimizing moisture-related issues in the crawl space.

2.2.5 Sealing Air Leaks

Sealing air leaks in the crawl space is crucial for moisture control. Use caulk or foam insulation to seal gaps, cracks, and openings in the crawl space walls, vents, and access doors. As a result, this will prevent the entry of humid outdoor air into the crawl space, reducing moisture buildup.

Conclusion

Maintaining a proper crawl space free of moisture is vital for preventing mold growth, wood damage, and pest infestation. Your ideal crawl space humidity level should be between 30% and 50%. By implementing effective moisture control methods such as ventilation, vapor barriers, a crawlspace dehumidifier, proper drainage, and sealing air leaks, you can create a healthy living environment and extend the lifespan of your home. Regular monitoring and maintenance will ensure the long-term health and integrity of your crawl space.

Remember, taking these proactive steps is a wise investment in the well-being of your home and the comfort of its occupants.